Feb. 20, 1952
DEHYDROGENATION O F &SUBSTITUTED 1,2,3,4-TETRAHYDRONAPHTHALENES
Acknowledgment.-The authors are grateful to Professor A. B. Burg of the University of Southern California for his helpful suggestions, and to Dr.
905
L. A. Burkardt for preparing the X-ray photographs* ~~
INYOKERN, P. 0. CHINALAKE.CALIF. RECEIVED JULY 16, 1951
[CONTRIBUTION FROM THE CHEMISTRY LABORATORY OF THEOHIO STATE UNIVERSITY]
The Catalytic Dehydrogenation of 5-Substituted 1,2,3,4-Tetrahydronaphthalene Derivatives BY MELVINS. NEWMAN AND THEODORE S. BYE' The syntheses of RCOOCH,, RCH20H, RCHIOCOCHs, RCOCH,, RCHpCOCHI and RCH2CH2COCHS,where R is the
1,2,3,4-tetrahydro-6naphthylradical, are described. The products arising from liquid phase catalytic dehydrogenation of
these compounds over palladium-on-charcoal are described and the results compared with those previously obtained with 1,2,3,4-tetrahydro-6-naphthyl,1,2,3,4-tetrahydro-l-naphthyland 1,2,3,4-tetrahydro-2-naphthylderivatives.
The work reported herein is a continuation of studies designed to obtain more information concerning the fate of oxygenated functions in hydroaromatic compounds when submitted to liquid phase dehydrogenation over palladium-on-charcoal. The previous reports dealt with 6-substituted 1,2,3,Ptetrahydronaphthalenes, B , 1-substituted 1,2,3,4-tetrahydronaphthalenesJaC, and 2-substituted
1,2,3,4-tetrahydronaphthalenesJ * D.
Since the oxygenated functions, OF, of B, C and D differed both in their positions with respect to the point of fusion and in their relative positions with respect to the hydrogen to be removed, it was necessary to study compounds of type A before a complete discussion could be attempted. In this paper, we describe the dehydrogenation of 5substituted-1,2,3,4-tetrahydronaphthalenes, A, under the above conditions. The results are summarized in Table I.
1.5431. Anal. Calcd. for CI,H,,O~: C, 75.8; H, 7.4. Found: C,75.4,75.3; H , 7.3,7.5. 1,2,3.,4-Tetrahydro-5-naphthylcarbinol(11).-During two hours, a solution of 110 g. (0.58 mole) of I in 800 ml. of anhydrous ether was dropped into an ethereal solution of 13.5 g. of lithium aluminum hydride.' After the reaction mix?ZSD
OF
A
B
C
The hydrogenation was carried out as a 20% ethanol solution, using a Raney nickel catalyst, a temperature of 130150' and a pressure of 50 atmospheres. After removal of the solvent, the mixture of hydrogenated esters was rectified t o yield 1532 g. (79.8%) of hydrogenated ester. B. Preparation of 1,2,3,4-Tetrahydro-S-naphthoic Acid. -This acid was obtained pure from the above mixture of esters in two ways. Thelast two fractions of ester, 365.7g., were combined and saponified with alcoholic potassium hydroxide. The acid, after recrystallization from 50% alcohol, weighed 283 g., m.p. 150.7-151.9°. The other fractions were saponified individually t o mixtures of 1,2,3,4tetrahydro-5naphthoic acid and 1,2,3,4tetrahydro-l-naphthoic acid. Separation was accomplished by fractional acidification from alkaline solution. Batches of two or three fractions of the mixture of acids were saponified and fractionally acidified according t o the principles outlined previously.? By this method, there was obtained 261 g. of pure 1,2,3,4-tetrahydro-5-naphthoic acid, m.p. 150.0-161.5". The total yield of pure acid was 544 g. (32.2% based on the ethyl a-naphthoate). Methyl 1,2,3,4-Tetrahydro-5-naphthoate (I).-The methyl ester prepared from the above acid in 90% yield formed a colorless liquid, b.p. 93.5-96.5' at 0.5-1.0 mm.,
D
Experimental6 1,2,3,4-Tetrahydro-5-naphthoic Acid. A. Hydrogenation of Ethyl a-Naphthoate.-The ester to be hydrogenated
was heated for two hours with Raney nickel a t 150". After cooling, the catalyst was a t e r e d and the ester rectified through a column with a one-foot packed section containing glass helices. There was obtained 1920 g. of pure ester. (1) This work was taken from the dissertation submitted by T. S. Bye to The Ohio State University in partial fulfillment of the requirements for the Ph.D. degree, March, 1951. (2) M. S. Newman and H. V. Zahm, THISJOURNAL, 66, 1097 (1943). (3) M. S. Newman and Fr. T. J. O'Leary, ibid., 68, 258 (1946). (4) M. S. Newman and J. R. Mangham, ibid., 71, 3342 (1949). ( 6 ) All melting points are corrected. Microanalyses marked by Mrs. E. K. Klotz; by Clarke Microanalytical Laboratory, Urbana, Illinois. (6) S. I. Sergievskaya and E. G. Nikhamkina, J . Ccn. Cbem. (U.S. S. R), 16,988 (1946). We wish to thank the Hooker Electrochemical Company, Niagara Falls, New York, for carrying out the large scale hydrogenation. The following sentences are quoted from a letter: "The hydrogenation was carried out as a 20% ethanol solution and it was found that three separate autoclave runs were required to process the solution. Our Operations Department advises us furthermore, that absorption was rapid and complete after the first hour but that the runs were continued for a total of 6 hours as advised in the reference."
'
ture had been decomposed with water and dilute sulfuric acid, distillation yielded 91.5 g. (97.7%) of the desired carbinol, 11, as a colorless viscous oil, b.p. 105-107" at 0.51.0 mm., n% 1.5682. I t s I-naphthylurethan melted at
136.7-137.7'. Anal. Calcd. for CtlHldO: 81.5; H , 8.6. Founde: C, 81.7; H , 8.6. Calcd. for C22H2102N: C, 79.8; H, 6.3; N,4.2. Founds: C,80.5,80.3; H,6.0,6.40 N, 4.3. The corresponding acetate, 111, was formed in 88% yield bv heating the carbinol. 11. in benzene with acetic anhvdride aAd a trace of p-toluenesuifonic acid. It formed a coioiess oil, b.p. 102' a t 0.4-0.8 mm., n% 1.5325. Ana2.c Calcd. for CtSH1602: C, 76.5; H, 7.9. Found: C, 76.3; H, 8.0. Methyl 1,2,3,4-Tetrahydro-S-naphthyIKetone (IV).Into a solution made from 12.2 g. (1.75 moles) of metallic lithium, 114 g. (0.8 mole) of methyl iodide and 500 ml. of anhydrous ether9 was slowly added a solution of 20 g. (0.114 mole) of RCOOH in 800 ml. of ether. The mixture was treated with water and the neutral portion distilled to yield 19.5 g. (99%) of the desired ketone, IV, as a colorless oil, b.p. 95.5-99.0' a t 0.5-1.0 mm., n% 1.5550. The semicarbazone melted at 221.5-223.5' with decomposition. (7) M. S. Newman, R. B. Taylor, T. Hodgson and A. B. Garrett, THIS JOURNAL, 69, 1784 (1947). (8) R. F. Nystrom and W. G.Brown, ibid., 69, 1197 (1947). (9) D. A. Van Dorp and J. F. Arens, Rcc. Irar. cbim., 65, 338 (1946).
MELVIN S. XEWMANAND THEODORE S. BYE
VOl. '75
TABLE I DEHYDROGENATION EXPERIMENTS
Compound"
No.
Time. hr.
Temp., "C.
3 .5 10.!)
279-322 265-2'76
H2
"io
Yield,b
Products
%
R'COOCH, 89.3
